SP/web2py/gluon/http.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
| This file is part of the web2py Web Framework
| Copyrighted by Massimo Di Pierro <mdipierro@cs.depaul.edu>
| License: LGPLv3 (http://www.gnu.org/licenses/lgpl.html)

HTTP statuses helpers
--------------------------------------------
"""

import re
from gluon._compat import iteritems, unicodeT, to_bytes

__all__ = ['HTTP', 'redirect']

defined_status = {
    200: 'OK',
    201: 'CREATED',
    202: 'ACCEPTED',
    203: 'NON-AUTHORITATIVE INFORMATION',
    204: 'NO CONTENT',
    205: 'RESET CONTENT',
    206: 'PARTIAL CONTENT',
    301: 'MOVED PERMANENTLY',
    302: 'FOUND',
    303: 'SEE OTHER',
    304: 'NOT MODIFIED',
    305: 'USE PROXY',
    307: 'TEMPORARY REDIRECT',
    400: 'BAD REQUEST',
    401: 'UNAUTHORIZED',
    402: 'PAYMENT REQUIRED',
    403: 'FORBIDDEN',
    404: 'NOT FOUND',
    405: 'METHOD NOT ALLOWED',
    406: 'NOT ACCEPTABLE',
    407: 'PROXY AUTHENTICATION REQUIRED',
    408: 'REQUEST TIMEOUT',
    409: 'CONFLICT',
    410: 'GONE',
    411: 'LENGTH REQUIRED',
    412: 'PRECONDITION FAILED',
    413: 'REQUEST ENTITY TOO LARGE',
    414: 'REQUEST-URI TOO LONG',
    415: 'UNSUPPORTED MEDIA TYPE',
    416: 'REQUESTED RANGE NOT SATISFIABLE',
    417: 'EXPECTATION FAILED',
    422: 'UNPROCESSABLE ENTITY',
    429: 'TOO MANY REQUESTS',
    451: 'UNAVAILABLE FOR LEGAL REASONS',  # http://www.451unavailable.org/
    500: 'INTERNAL SERVER ERROR',
    501: 'NOT IMPLEMENTED',
    502: 'BAD GATEWAY',
    503: 'SERVICE UNAVAILABLE',
    504: 'GATEWAY TIMEOUT',
    505: 'HTTP VERSION NOT SUPPORTED',
    509: 'BANDWIDTH LIMIT EXCEEDED',
}

regex_status = re.compile('^\d{3} [0-9A-Z ]+$')


class HTTP(Exception):
    """Raises an HTTP response

    Args:
        status: usually an integer. If it's a well known status code, the ERROR
          message will be automatically added. A string can also be passed
          as `510 Foo Bar` and in that case the status code and the error
          message will be parsed accordingly
        body: what to return as body. If left as is, will return the error code
          and the status message in the body itself
        cookies: pass cookies along (usually not needed)
        headers: pass headers as usual dict mapping
    """

    def __init__(
        self,
        status,
        body='',
        cookies=None,
        **headers
    ):
        self.status = status
        self.body = body
        self.headers = headers
        self.cookies2headers(cookies)

    def cookies2headers(self, cookies):
        if cookies and len(cookies) > 0:
            self.headers['Set-Cookie'] = [
                str(cookie)[11:] for cookie in cookies.values()]

    def to(self, responder, env=None):
        env = env or {}
        status = self.status
        headers = self.headers
        if status in defined_status:
            status = '%d %s' % (status, defined_status[status])
        elif isinstance(status, int):
            status = '%d UNKNOWN ERROR' % status
        else:
            status = str(status)
            if not regex_status.match(status):
                status = '500 %s' % (defined_status[500])
        headers.setdefault('Content-Type', 'text/html; charset=UTF-8')
        body = self.body
        if status[:1] == '4':
            if not body:
                body = status
            if isinstance(body, (str, bytes, bytearray)):
                if isinstance(body, unicodeT):
                    body = to_bytes(body) # This must be done before len
                headers['Content-Length'] = len(body)
        rheaders = []
        for k, v in iteritems(headers):
            if isinstance(v, list):
                rheaders += [(k, str(item)) for item in v]
            elif v is not None:
                rheaders.append((k, str(v)))
        responder(status, rheaders)
        if env.get('request_method', '') == 'HEAD':
            return ['']
        elif isinstance(body, (str, bytes, bytearray)):
            if isinstance(body, unicodeT):
                body = to_bytes(body)
            return [body]
        elif hasattr(body, '__iter__'):
            return body
        else:
            body = str(body)
            if isinstance(body, unicodeT):
                body = to_bytes(body)
            return [body]

    @property
    def message(self):
        """
        compose a message describing this exception

            "status defined_status [web2py_error]"

        message elements that are not defined are omitted
        """
        msg = '%(status)s'
        if self.status in defined_status:
            msg = '%(status)s %(defined_status)s'
        if 'web2py_error' in self.headers:
            msg += ' [%(web2py_error)s]'
        return msg % dict(
            status=self.status,
            defined_status=defined_status.get(self.status),
            web2py_error=self.headers.get('web2py_error'))

    def __str__(self):
        """stringify me"""
        return self.message


def redirect(location='', how=303, client_side=False, headers=None):
    """Raises a redirect (303)

    Args:
        location: the url where to redirect
        how: what HTTP status code to use when redirecting
        client_side: if set to True, it triggers a reload of the entire page
          when the fragment has been loaded as a component
    """
    headers = headers or {}
    if location:
        from gluon.globals import current
        loc = location.replace('\r', '%0D').replace('\n', '%0A')
        if client_side and current.request.ajax:
            headers['web2py-redirect-location'] = loc
            raise HTTP(200, **headers)
        else:
            headers['Location'] = loc
            raise HTTP(how,
                       'You are being redirected <a href="%s">here</a>' % loc,
                       **headers)
    else:
        from gluon.globals import current
        if client_side and current.request.ajax:
            headers['web2py-component-command'] = 'window.location.reload(true)'
            raise HTTP(200, **headers)